1. Field of the Invention
The present invention relates to a digital data reproducing and recording apparatus, and a digital data reproducing and recording method. More particularly, the present invention relates to an apparatus and method for reproducing and recording digital data such as music, audio and video, which can be distributed through a digital communication network.
2. Prior Art
The industrial field of digital communications has recently developed, in which various contents of digital data are distributed through a digital communication network. The contents of digital data, unlike those of analog data, do not suffer from distortion during transmission, and this makes it possible to distribute the digital contents to users through a network. The use of a digital communication network allows the users to easily download from the network the digital contents such as music, audio and video, which are conventionally difficult to get from a remote place or abroad.
However, since the data is digitized, it is easy to make duplicates of the data, resulting in a flood of duplicates with the quality equivalent to that of the original. This causes danger of threatening all rights of suppliers from which digital contents are distributed through the network, acting as a brake on advances in this field.
To avoid this, some suppliers try to protect the contents in such a way that a guard or protective signal is premixed in the contents to prohibit all users from reproducing the data unless they make a certain contract with the supplier, or that times of reproduction operations or a total playing time is limited under the contract conditions made at the time of purchase, to thereby prohibit the users from reproducing the data over the limited times of reproduction operations or the limited playing time. The former method, however, cannot prevent someone from reproducing the data in breach of contract using a tool for releasing the protective signal superimposed in the data. The latter method also allows someone to release the limit by altering management information managed by a player machine.
Some other suppliers offer data contents for onetime replay on a trial basis. In this case, the data contents are erased and removed from a memory of the player after onetime replay. This attempt will, however, end in failure if a user make a duplicate before the data contents are erased.